Created_at or updated_at not displaying full dateTime

In my laravel app i need to compare 2 dateTime, the created_at and the updated_at, but i notice that when i call this properties of the record is not disaplayed the seconds, onlu hour and minutes, i need to get the seconds, what i need to change or include to show all info? I beend checking on the documentation and didnt found anything.

Ex:

$calculation->created_at

output:

2017-03-03 21:03

And in database is:

2017-03-03 21:03:22

via Chebli Mohamed